During manufacture of a commercial aircraft, hundreds of thousands of precisely located, straight holes may be drilled. These holes are drilled by robotic systems that include drilling end effectors.
After a group of holes has been drilled, the drilled holes are inspected to ensure that they are within tolerance. The inspection does not simply involve checking a single hole diameter. Rather, the inspection involves checking the diameter and circularity of each hole at different depths to ensure that each hole is straight (and not conical or hourglass-shaped). Typically, the inspection is performed by a quality assurance (QA) inspector, who inspects large groups of holes at one time.
Consider a situation where a drill bit becomes chipped while drilling a hole. Due to the chipped bit, the drilled hole is out of tolerance. Subsequent holes drilled by the chipped bit are also out of tolerance. Unfortunately, those subsequent out-of-tolerance holes are not identified until QA inspection.
It would be desirable to minimize the number of holes drilled by a damaged bit. More generally, it would be desirable to minimize the number of out-of-tolerance holes.